Method of making piles in place



Sept 9, l930- J. H. THORNLEY 1,775,217

METHOD OF MAKING PILES IH PLACE Filed Nov. 2, 1927 Patented Sept. 9,1930 UNITED STATES PATENT OFFICE JOSEPH H. THORNLEY, OF CHICAGO,ILLINOIS, ASSIGNOR TO WESTERN FOUNDATION COMPANY, 0F CWICAGO, ILLINOIS,A CORPORATION OF ILLINOIS METHOD OF MAKING PILES IN PLACE Applicationfiled November 2, 1927. Serial No. 230,434.

The present invention pertains to cast-inplace concrete piles and to animproved method of making the same. More specifically, the inventionrelates to that type of cast-inplace pile having an enlarged lower endor pedestal portion.

One of the objects of the invention is to provide an improved method ofexpanding or forcing the concrete outwardly at the bottom of the hole inthe formation of the enlarged pedestal portion. According to this methodof forming the pedestal portion, the expansive pressure is applied tothe concrete in such manner that the major portion of the pressure actslaterally and downwardly, so that the reaction pressures of the soilagainst the pedestal portion will be in the proper direction for givingthe maximum load bearing value to the finished pile.

Another object of the invention is to provide an improved method ofbonding the column portion of the pile to the expanded pedestal portion.According to this method, the column portion of the pile has a socketedbonding in the pedestal portion of the pile, i. e., in the formation ofthe pedestal portion a vertical socket is formed therein in which thecolumn portion of the pile is cast. In the preferred construction, thecolumn portion of the pile comprises a corrugated tubular shell whichextends down into this socket, whereby the corrugations of the shellestablish an interlocking bond between the pedestal portion and columnportion of the pile.

Other objects and advantages of the invention will appear in thefollowing description of the preferred manner of carrying out myinvention. In the drawing accompanying this description:

Figures 1, 2, 3 and 4 are vertical sectional views through the lowerportion of the hole in which the pile is to be cast, illustratingsuccessive steps in the formation of the pile; and

Figure 5 is a similar sectional view showing the lower portion of thecompleted pile.

The hole in which the pile is to be cast is sunk in any preferred mannersuch as by driving, jetting or digging, depending upon the character ofthe soil through which the `core to compact its mass.

operation is carried. The present invention 1s not concerned with themethod of sinking the hole, 1t being desirable, however, that a suitablecasing line the hole after its completion, such casing either beingcarried down progressively with the sinking of the hole or beingthereafter inserted.

Referring to Figure 1, the hole is indicated at 8, and the casingreferred to is indicated at 9. After the hole has been sunk to thedesired depth, and with the lower end of the casing 9 sustaining theside walls of the hole against collapse, a charge of concrete 1l isdumped into the lower end of the casing. This charge is suflicientlylarge to form the main body of the pedestal portion. A ram or core 12 isthen lowered into the casing to bring its lower end into contact withthe charge of concrete 11. If desired, the charge may be tamped lightlya few times by the i The next step in the operatlon is illustrated inFigure 2, and consists in drawing the casing 9 upwardly to bring itslower edge into proximity to the lower end of the core or ram l2,meanwhile holding the core pressed downwardly against the top of thecharge of concrete 11. The weight of the core will ordinarily besuiiicient to hold it down upon the concrete, but if there is anytendency for the core to rise with the casing such is overcome byholding a stationary abutment against the upper end of the core,'in amanner well known. As the casing is pulled upwardly, the concrete willexpand outwardly into the space occupied by the casing, the ram 12following the slight downward recession of the top of the concretecharge as this outward expansion takes place. Aj shown in Figure 3, theupper end of the casing is provided with the usual hoisting collar 13,with which any suitable hoisting tackle may be connected for lifting thecasing. It will be evident that by thus lifting the casing and holdingthe ram in place, the pedestal forming charge of concrete 11 will bestripped out of the casing, remaining in the bottom of the hole 8 andcoming into direct contact with the side Walls thereof. The density ofthe concrete will prevent any possibility of the sides of the holecollapsing inwardly during the lifting of the casing.

The next step in the operation is illustrated in Figure 3, and consistsin forcing the core and casing downwardly into the charge of concrete,the core and casing operatingl as a unitary spreading or pressuremember. To facilitate concurrent downward movement of the core andcasing the upper end of the core is provided with a head 14 which isadapted to bear upon the hoisting collar 13 of the casing when the lowerends of the core and casing are in proximity to each other, as shown. 1nFigures 2 and 3.. By transmitting drivlng blows to the head 14 the coreand casing will move downwardly as a unit through the engagement of thehead 14 with the collar 13. In such downward movement, the charge ofconcrete will be crowded outwardly against the side walls of the hole 8,compressing the soil outwardly to enlarge the hole, and resulting in theconcrete assuming the enlarged or bulb-shaped formation indicated at 11.1n Figure 3. The descent of the core and casing is preferably limited sothat they will not pass entirely through the concrete, but will leave aconsiderable thickness thereof at the bottom of the pedestal formation11. The result of this ramming operation is to expand the concreteoutwardly, as above described, and to produce a longitudinal socket 15in the pedestal formation, which socket extends down axially from thetop of the pedestal to a point adjacent to the bottom thereof.

Certain important advantages accrue to l this method of expanding theconcrete. Heretofore, the practice most generally followed has been toconfine a charge of concrete within the lower portion of the casing, andto force such charge down out of the end of the casing by downwardmovement of a ram within the casing. Sufficient pressure is exerteddownwar-dly on the charge of concrete to compel it to flow out of thecasing and to expand outwardly below the end of the casing into pressurecontact with the earth walls, the fluid pressure of the concretecompressing the earth walls and enlarging the bottom of the holesufficiently to produce the enlarged pedestal formation. This priormethod is based upon a fluid iiow of the concrete, requiring acomparatively wet mix thereof, such fluid flow resulting in the pressureimparted to the charge being transmitted substantially equally in alldirections. Hence a considerable part of the'pressure acts upwardly onthe soil superposed over the pedestal formation, and, in consequence,the reaction of this superposed soil is downwardly, which detracts fromthe load bearing Value of the pile in so far as carrying compressionloads is concerned.

Such objection is avoided in the practice of the present method. Owingto the fact that the expansion of'the concrete outwardly results more byvirtue of the physical displace mass, there is very little tendency forthe concrete to establish upwardly acting pressures against the soilsuperposed over the pedestal formatlon. The mechanicaldisplacement ofthe concrete creates outwardly and downwardly acting pressures therein,which establish reaction pressures in the soil acting inwardly andupwardly with respect to the pedestal formation, thereby giving a firmanchorage to the pedestal and giving a, maximum load bearing value tothe pile. Moreover, the present method results'in the formation of along socket in the pedestal, as above remarked, which socket is adesirable feature for anchoring the column portion of the pile, as Ishall now describe.

After the core and casing have been driven down into the concrete to thedesired depth, the core is withdrawn, leaving the casingwithin thepedestal formation in order to maintain the formation of the socket 15against the inwardly acting pressure of the concrete. The next step inthe operation is illustrated in Figure 4, and comprises lowering a lightcrete is dumped into the interior of the shell,

preferably to fill the same completely. Such additional concrete isindicated at 17 in Fig.

5. Preparatory to dumping this additional concrete, any suitablereinforcing means may be inserted in the shell, represented, forexample, by the relatively heavy bar indicated at 18 in Figure 5.' Theouter casing 9 forms no part of the completed pile, and is withdrawneither before the additional concrete 17 is dum ed into the shell 16, orafter the shell has een filled with concrete. Where the soil is ofsuch-character that it is possible that the earth pressure mightcollapse the light shell 16, itis, of course, desirable to retain thecasing 9 in the ground as a protecting element until the light shell hasbeen filled with concrete.

The withdrawal ofthe casing allows the concrete in the pedestal portionto move back into direct adhesive contact with the corrugations of thelight shell. Thus as soon as the concrete sets the pedestal portion 11has interlocking engagement with the shoulders 16 formed by the annularcorrugations in the shell.v Similarly the concrete 17 within the shellhas interlocking engagement with the inner shoulders formed, by theannular corruiso the column portion 17 have bonded engagement throughthe walls of the shell throughout the entire length of that portion ofthe shell which is embedded in the pedestal.

' Cementitious bonding will also occur between the lower end of thecolumn portion and the lower stratum extending across the bottom of thepedestal portion. It will be observed that by forming the socketl in thepedestal portion, the reinforcing means 18 can be' extended down intothe body of the pedestal portion so that the stresses transmitted tothis reinforcing Vmeans will be distributed throughout substantially theentire body portion of the pedestal.

It will be observed that at no stage in the operation of casting thepile is there any opportunity for sub-surface water to enter between thepedestal and the column, or for such water to enter or have contact atany other point where it might deleteriously aii'ect the casting of thepile. The long length of bonded joint between the column portion andpedestal portion gives a high tensile strength to the finished pile, andit will be observed that by extending the shell 16 down into thepedestal portion there is no possibility of upwardly acting earthstresses causing the column portion to separate from the pedestalportion before the concrete has set.

While I prefer to construct the column portion of the pile as acast-in-place structure consisting of the shell 16 and concrete fillin17, nevertheless it will be understood tha some of the advantages of theinvention lcan be realized by constructin the edestal portion in themanner above escri ed and then seating a pre-cast concrete Eile, or anyother type of completed pile wit 'n the socket 15 for bonding with thepedestal portion.

What I claim as my invention and desire to secure by Letters Patent, is

1. The method of forming cast-in-place piles which comprises de siting acharge of concrete in the hole in w 'ch the pile is to be formed indirect contact with the earth walls thereof, and ramming a core andcasing down into said charge to expand the latter out wardly and to forma vertical socket within the expanded charge of concrete, which sc cketis retained against collapse by said casing when said core is withdrawn.

2. The method of forming' cast-in-place piles which comprises depositina charge of concrete in the hole in contact with the earth wallsthereof, ramming a core and .casing down into said charge for expandinthe latter outwardly to form an enlarged estal portion having a verticalsocket therein, withdrawing the core while said casing maintains theform of said socket, and completing the pile with the column portionthereof extendmg down into said socket.

The method of forming castinplace piles which comprises depositing acharge of concrete in the bottom of the holein which the pile is to beformed, ramminga core and casing down into the charge to ex and thelatter outwardl around the outer sides of the casing in the orm of anenlarged pedestal portion, withdrawing said core while retaining saidcasing within said pedestal portion, lowering a shell within said casingto have its lower end extend into said pedestal portion, dumpingconcrete into said shell, and withdrawing said casing.

4. The method of forming cast-in-place piles which comprises sinking ahole in which` the pile is to be formed, extending a casing down intosaid hole adjacent to the bottom thereof, depositing a charge ofconcretewithin said casing, raising said casing a predetermined distance toallow the concrete to contact directl with the earth walls at the bottomof the hole, driving said casing with a core therein down into saidcharge of concrete for expanding the latter outwardly andv to line thesides thereof substantially to the l bottom of said hole, dumping adestal forming charge of concrete intosai casing, placing a core withinsaid casing to bear upon said charge of concrete, raisin said casing alpredetermined distance whi e said core forces the concrete out of thelower end of said casinlg into direct contact with the earth walls at te bottom of the hole, driving said core and casing downwardl as a unitinto the charge of concrete, there y spreading the charge outwardlagainst the earth walls for producing an en ar ed pedestal portion andalso formin a soc et extending down into said pedesta portion,withdrawing said corewhile retainin said casing its driven walls of saidsocket, lowering a corrugated shell within said casing to have its lowerend extend down approximately to the bottom of said socket, placingreinforcing means within said shell, dumping additional concrete intothe same for stantially filling said shell, and withdrawin said casingafter said shell has been lowere into said socket.

JOSEPH H. THORNLEY.

substantially in sition for sustaining the side

